Acloud: Reusing existing instance.

- Stop AVD in the current instance.
- Clean images in the current instance.
- Process artifacts.
- Launch AVD and with boot up

Bug:137325264
Bug:123721459
Test: acloud-dev create --reuse-gce {instance_name}
      acloud-dev create --reuse-gce
      acloud-dev create
      acloud-dev create --reuse-gce {instance_name} --local-image
      acloud-dev create --reuse-gce --local-image
      acloud-dev create --local-image

Change-Id: I0fcae4ce649315205f7461bbc626185437e3af3e
9 files changed